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Electrical hum when stepping up usb to 9v Answered

Hi. I'm wanting to power some lights with usb. I'm using a 5v to 9v step-up board to get the correct voltage. This works, however, the step-up board makes a humming noise. Is there a way to eliminate the hum? Thanks!

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Josehf Murchison
Josehf Murchison

1 year ago

The buck booster or joule thief is running under 2 kHZ sometimes you can change the frequency beyond audible, however if you don't know what you are doing chances are you will mess it up.
Stabilizing the coil in silicone can suppress the noise sometimes.
Easier to look for a 5v to 9v buck booster or Joule thief well over 20,000 HZ (2 kHZ) if you don't know much about Electronics.

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Orngrimm
Orngrimm

1 year ago

Squeeling noises are often attributed to the coil in the DC-DC-Converter.
If there is an open coil on your DC/DC try to hotglue it down.
Also, try to use a DC/DC which has a freq of many 100kHz and not the cheapo chinese ones with 10-15k and superimposed resonance on 1-2kHz...

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Jack A Lopez
Jack A Lopez

1 year ago

Is it a hum or a squeal?

By the way, the only difference between those is a squeal is faster, and higher pitched, than a hum.

Actually, both words are onomatopoeic, so a hum kind of sounds like the word "hum," and a squeal kind of sounds like the word, "squeal."

I guess what I am saying is, I would maybe expect high-pitched, audible noise, because the oscillators in these switching converters run very fast (typically 10s of KHz). In contrast, mains power hum has its (very low) fundamental frequency at 50 or 60 Hz.

Also, often the loudness of audible switching noise, depends on how hard the converter is working; i.e. how much power is moving through it.

You know, this "to get the correct voltage" is just one consideration. The other consideration is current, or equivalently power (since power=voltage*current).

If you are loading this converter with more power than it is comfortable supplying, then the noise it makes is perhaps it crying out in pain.

The other symptom of overloading, i.e. too much power throughput, is heat. If components on the board are getting hot, that is usually a bad sign.

Final note, regarding a way to test this hypothesis of mine, regarding audible noise related to power throughput:

Does the noise go away when you disconnect the lights?

Is the noise only half as loud, when half the load is connected (e.g. lights using half as much power)?